Relic density and PAMELA events in a heavy wino dark matter model with Sommerfeld effect

Abstract

In a wino LSP scenario the annihilation cross section of winos gravitationally bound in galaxies can be boosted by a Sommerfeld enhancement factor which arises due to the ladder of exchanged W bosons between the initial states. The boost factor obtained can be in the range S ~ 10^4 if the mass is close to the resonance value of M ~ 4 TeV. In this paper we show that if one takes into account the Sommerfeld enhancement in the relic abundance calculation then the correct relic density is obtained for 4 TeV wino mass due to the enhanced annihilation after their kinetic decoupling. At the same time the Sommerfeld enhancement in the χχ--> W^+ W^- annihilation channel is sufficient to explain the positron flux seen in PAMELA data without significantly exceeding the observed antiproton signal. We also show that (e^- + e^+) and gamma ray signals are broadly compatible with the Fermi-LAT observations. In conclusion we show that a 4 TeV wino DM can explain the positron and antiproton fluxes observed by PAMELA and at the same time give a thermal relic abundance of CDM consistent with WMAP observations.

24 pages, 12 figures, 1 table; title corrected in arxiv metadata

References in corpus (16)

• Observation of an anomalous positron abundance in the cosmic radiation
• A Theory of Dark Matter
• Measurement of the Cosmic Ray e+ plus e- spectrum from 20 GeV to 1 TeV with the Fermi Large Area Telescope
• micrOMEGAs2.0: a program to calculate the relic density of dark matter in a generic model
• A new measurement of the antiproton-to-proton flux ratio up to 100 GeV in the cosmic radiation
• PAMELA results on the cosmic-ray antiproton flux from 60 MeV to 180 GeV in kinetic energy
• The Spectrum of the Isotropic Diffuse Gamma-Ray Emission Derived From First-Year Fermi Large Area Telescope Data
• CMB Constraints on WIMP Annihilation: Energy Absorption During the Recombination Epoch
• Non-perturbative Effect on Thermal Relic Abundance of Dark Matter
• Search for a Dark Matter annihilation signal from the Galactic Center halo with H.E.S.S
• Constraints on WIMP Dark Matter from the High Energy PAMELA $\bar{p}/p$ data
• The Fermi-LAT high-latitude Survey: Source Count Distributions and the Origin of the Extragalactic Diffuse Background
• Measurements of cosmic-ray secondary nuclei at high energies with the first flight of the CREAM balloon-borne experiment
• TeV gamma-rays and the largest masses and annihilation cross sections of neutralino dark matter
• Dark matter and pulsar signals for Fermi LAT, PAMELA, ATIC, HESS and WMAP data
• Looking for a heavy wino LSP in collider and dark matter experiments

Cited by in corpus (10)

• Relic densities including Sommerfeld enhancements in the MSSM
• Non-Universalities in Pure Gravity Mediation
• Flavor unification, dark matter, proton decay and other observable predictions with low-scale $S_4$ symmetry
• Standard Coupling Unification in SO(10), Hybrid Seesaw Neutrino Mass and Leptogenesis, Dark Matter, and Proton Lifetime Predictions
• Dark Matter in Split SUSY with Intermediate Higgses
• Supersymmetric Left-Right Model of Radiative Neutrino Mass with Multipartite Dark Matter
• On the stability of particle dark matter
• Extracting the size of the cosmic electron-positron anomaly
• SU(5) unification of two triplet seesaw and leptogenesis with dark matter and vacuum stability
• SUSY Dark Matter in Universal and Nonuniversal Gaugino Mass Models